Abstract

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the masks being used in order to maintain exquisite control over both feature size and feature density. Here, the authors demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top–down atomic control over nanofabrication. First, hydrogen depassivation lithography is performed on hydrogen terminated Si(100) using a scanning tunneling microscope, which spatially defined chemically reactive regions. Next, atomic layer deposition of titanium dioxide produces an etch-resistant hard mask pattern on these regions. Reactive ion etching then transfers the mask pattern onto Si with pattern height of 17 nm, critical dimension of approximately 6 nm, and full-pitch down to 13 nm. The effects of linewidth, template atomic defect density, and line-edge roughness are examined in the context of controlling fabrication with arbitrary feature control, suggesting a possible critical dimension down to 2 nm on 10 nm tall features. A metrology standard is demonstrated, where the atomically resolved mask template is used to determine the size of a nanofabricated sample showing a route to image correction.

This work was supported by a Contract from DARPA (N66001-08-C-2040) and by a grant from the Emerging Technology Fund of the State of Texas. Certain equipment and materials are described in this article in order to specify clearly the experimental procedures used. In no case does this imply a recommendation by the National Institute of Standards and Technology or that the equipment or materials are necessarily the best available for the purpose.